MGMT and central nervous system cancer: These include MGMT (unmethylated methylguanine methyltransferase) promoter methylation, predictive of sensitivity to alkylating agents; IDH1 (isocitrate dehydrogenase) mutations, common in most low-grade gliomas and secondary high-grade gliomas; and the CpG island methylator phenotype (G-CIMP), which correlates with a more favorable prognosis [3].